Japanese Patent Application Laid-Open (JP-A) No. 2010-23538 describes technology in which a reinforcement member spans between a front portion side of a side sill (rocker) and a floor frame (floor side member) at an angle. A join portion between the reinforcement member and the floor frame is provided with a weakened portion that has lower strength than other portions of the floor frame, and the weakened portion deforms in the event of a vehicle frontal collision, thereby suppressing deformation of an overall floor panel.
JP-A No. 2013-203111 describes technology provided with a reinforcement member with a closed cross-section structure that joins a torque box and a front side frame together.